Embodiments of the present invention relate to a technology for wirelessly transmitting and receiving signals and power, and more particularly, to a technology for transmitting and receiving a signals and power between integrated circuit (IC) chips or between an IC chip and test equipment in a near field.
Before many types of ICs, including memories, are delivered to customers, whether the ICs operate normally is tested before and after a packaging step. This includes testing the ICs during a wafer test step, before the ICs formed on a wafer are singulated into individual IC chips. In the related art, the wafer test step is performed by placing probe tips, referred to herein as needles, in contact with pads of an IC formed on the wafer and transmitting and receiving signals using the needles. The needles used in the wafer test step are formed on a probe card. The number of needles on the probe card corresponds to the product of the number of IC chips which can be simultaneously tested using the probe card, which may include all of the IC chips formed on one wafer, and the number of pads to be probed in each IC chip.
In a wired test scheme in which signals are transmitted and received using needles formed on a probe card, problems arise from having a large number of needles on the probe card. Particularly, an increase in the number of ICs formed on each wafer, in the number of ICs simultaneously tested using the probe card, and/or in the number of pads formed on an IC results in an increase in the number of needles. The increased number of needles produces an increase in a pressure applied to a wafer by the probe card.
To solve the problems of the aforementioned wired test scheme, a technology has been proposed in which signals are wirelessly exchanged between an IC on a wafer and a probe card, or wirelessly exchanged between a plurality of IC chips stacked in one package. The technology uses the wireless signal transmission/reception technology using inductively coupled coils disclosed in Korean Patent Reg. No. 1066128.